WO2003039813A1

WO2003039813A1 - Wrench

Info

Publication number: WO2003039813A1
Application number: PCT/KR2002/001864
Authority: WO
Inventors: Tae-Hwan Ha
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-11-05
Filing date: 2002-10-07
Publication date: 2003-05-15
Anticipated expiration: 2004-05-05
Also published as: KR200261464Y1

Abstract

Motivated to provide a wrench of reduced free play, this invention provides a wrench having: a housing having an interior hole; a handle for supplying torque to the housing; and a fastening unit, being disposed in the interior hole of the housing, rotatable in one direction relative to the housing.

Description

TITLE OF THE INVENTION WRENCH

BACKGROUND OF THE INVENTION

(a) Field of the Invention The present invention relates to a wrench for manipulating fasteners such as bolts and nuts.

(b) Description of the Related Art

Fasteners such as bolts and nuts are widely used in order to conjoin separate parts, and various types of wrenches have been devised and used

in order to manipulate, that is, to tighten or loosen, such fasteners.

For example, an open end wrench and a box end wrench are simple types of such wrenches.

When manipulating fasteners (a bolt is hereinafter used as an

example of a fastener) with such simple types of wrenches, inconvenience of engaging and disengaging the wrench with the bolt is incurred at each stroke of tightening or loosening the bolt. Ratchet wrenches have therefore been devised and utilized in order to solve such inconvenience.

Such conventional ratchet wrenches enable continuous operation while maintaining engagement with the bolt, and therefore the utility of the

wrench is increased.

However, such conventional ratchet wrenches, according to their

mechanical structure, have free play even when the wrench is tightly fitted to

a fastener. Therefore, it is difficult to manipulate a fastener in a circumstance

wherein a space to rotate the wrench is small. Furthermore, such free play increases as wear of constituent parts of a wrench increases according to accumulated usage, and in this case, the difficulty also increases.

SUMMARY OF THE INVENTION

Therefore, the motivation for the present invention is to provide a-

wrench that has a non-limiting advantage of reduced free play.

An exemplary wrench useful with the present invention includes: a housing having an interior hole; a handle for supplying torque to the housing; and a fastening unit, being disposed in the interior hole of the housing, rotatable in one direction relative to the housing. The one directional rotatability of the fastening unit may be realized

when the fastening unit preferably includes: a fastening body having an exterior circumference, wherein a slope surface is formed at the exterior circumference such that a depth of the slope surface from the exterior circumference increases as a distance from an outward end of the slope surface increases; a clutch member disposed between the slope surface and the housing; and an elastic unit adapted to provide an outward biasing force

to the clutch member.

The slope surface may be planar, and a cross-section of the clutch

member is preferably circular such that the clutch member can roll on the

slope surface.

The elastic unit can be realized by an elastic member abutted by the fastening body and a piston disposed between the elastic member and the clutch member. In this case, an operation hole, having a predetermined

angle with the slope surface, is preferably formed at an end of the slope surface, and the elastic member and the piston are preferably disposed in

the operation hole.

In the exemplary wrench useful with the present invention, it is

preferable that a plurality of slope surfaces is symmetrically provided.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and

constitute a part of the specification, illustrate an embodiment of the invention, and, together with the description, serve to explain the principles of

the invention: FIG. 1 is an exploded perspective view of a wrench according to a preferred embodiment of the present invention;

FIG. 2 is a partial cross-sectional view of a wrench according to a preferred embodiment of the present invention;

FIG. 3 illustrates a power stroke of a wrench according to a preferred embodiment of the present invention; and

FIG. 4 illustrates a free stroke of a wrench according to a preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A preferred embodiment of the present invention will hereinafter be described in detail with reference to the accompanying drawings.

As shown in FIG. 1 , a wrench 100 according to a preferred embodiment of the present invention includes a housing 101 having a handle

102 formed thereon, with a fastening unit 1 10 being disposed inside the housing 101 , being rotatable in one direction relative to the housing 101 . A hole of a predetermined radius is formed at the housing 101 , the fastening unit 1 10 is disposed therein, and a snap ring 103 is provided to prevent separation of the fastening unit 1 10 from the hole.

FIG. 1 shows that a snap ring 103 is preferably disposed at both upper and lower sides of the housing 101. However, it is also preferable that the snap ring 103 is disposed at only one of the upper and lower sides of the

housing 101 , and that the other side of the housing 101 protrudes toward the center of the hole such that the fastening unit 1 10 is supported by the

protrusion. The fastening unit 1 10 includes a fastening body 120, a piston 130, a

spring 135, and a clutch member 140.

A hole for receiving a fastener is formed at a center of the fastening body 120, and accordingly a fastening surface 121 , the inner surface of the

fastening body 120, is shaped as a polygon having a predetermined number of planes. The predetermined number of planes of the polygon may be arbitrarily preset by a person skilled in the art, and it is preferably preset as one of 6 and 12.

A slope surface 122 is formed at an exterior circumference of the fastening body 120 such that the slope surface 122 forms a predetermined angle with a tangential direction of the exterior circumference.

Accordingly, room for accommodating the clutch member 140 is

formed by the slope surface 122. The clutch member 140 is of a shape of a cylinder such that the clutch member 140 can roll on the slope surface 122.

As shown in detail in FIG. 2, an operation hole 125 of a

predetermined radius and depth, and having a predetermined angle with the slope surface 122, is formed at an end of the slope surface 122. A spring 135 is disposed inside the operation hole 125, an end of the spring 135 being abutted by an inner wall of the hole 125, and a piston 130 is connected

to another end of the spring 135. Accordingly, the spring 135 supplies a biasing force on the piston 130

such that the piston 130 pushes the clutch member 140 outward.

Therefore, as can be clearly seen from the partially enlarged view in FIG. 2, the piston 130 comes in contact with both the slope surface 122 and

an interior surface of the housing 101 by the biasing force of the spring 125. A plurality of slope surfaces 122 are formed at the exterior of the fastening body 120, and FIG. 2 shows that five slope surfaces 122 are formed at the fastening body 120. However, the number of slope surfaces 122 can be varied according to choice of a person skilled in the art.

In the case that a plurality of slope surfaces 122 are formed, it is preferable that the plurality of slope surfaces 122 are disposed symmetrically such that a tightening/loosening force of the wrench 100 can also be symmetrically distributed.

At each of the plurality of slope surfaces 122, a clutch member 140, a

piston 130, and a spring 135 are disposed in the same way that has been described above with reference to the partially enlarged view in FIG. 2.

Although FIG. 2 illustrates that the slope surface 122 is planar, the shape of the slope surface 122 is not limited to be planar. On the contrary,

the slope surface 122 can be of any shape such that the depth from the exterior circumference of the fastening body 120 to the slope surface 122 increases as the distance from an outward end of the slope surface 122 increases.

Operation of the wrench 100 according to a preferred embodiment of the present invention is hereinafter described in detail with reference to FIGS.

3 and 4. In order to manipulate a fastener 300 using the wrench 100, the fastener 300 is inserted into the fastening body 120 and is fitted by the

fastening surface 121 of a polygonal shape (for example, a twelve-angled shape is shown in this preferred embodiment), and subsequently the wrench 100 is rotated using the handle 102. According to the embodiment of this invention, the fastener 300 is either tightened or loosened according to the

side of the wrench 100 that is placed over the fastener and to the direction that the wrench 100 is rotated.

FIG. 3 illustrates how the fastener is tightened.

When the wrench 100 is rotated in a clockwise direction as shown in FIG. 3, the clutch member 140 receives clockwise rotating force because of friction between the housing 101 and the clutch member 140. Therefore, the clutch member 140 is forced to roll outward on the slope surface 122 of the fastening body 120.

In this case, because the depth from the exterior circumference of the

fastening body 120 decreases as the distance from an outward end of the slope surface 122 decreases, the clutch member 140 becomes more tightly jammed between the housing 101 and the slope surface 122, and accordingly, a sufficiently large rotating force can be transmitted to the

fastening body 120. Although FIG. 3 illustrates a case wherein a rotating force in a clockwise direction is supplied, it also provides an understanding of the case wherein a rotating force in a counterclockwise direction is supplied, because in order to a supply counterclockwise rotating force, the wrench 100 can be

simply turned over. According to the operation described above, the fastener 300 can be tightened or loosened.

Such forcing and rotating the fastener 300 by a degree is referred to as a "power stroke" hereinafter. Repeated application of the power stroke to the fastener 300 enables tightening or loosening of the fastener 300 to a desired position.

In order to repeatedly apply the power stroke without disengaging the wrench 100 from the fastener 300, the wrench 100 is rotated in the direction opposite to that of the power stroke (with respect to the example of a power stroke shown in FIG. 3, in a counterclockwise direction). Such rotating of the wrench 100 in the direction reverse to the power stroke is referred to as "free stroke" hereinafter.

Operation of the wrench 100 in the free stroke is hereinafter described in detail with reference to FIG. 4.

When the wrench 100 is rotated in a counterclockwise direction as shown in FIG. 4, the clutch member 140 receives a counterclockwise rotating

force because of friction between the housing 101 and the clutch member 140.

Therefore, the clutch member 140 is forced to roll inward on the

slope surface 122 of the fastening body 120, and be released from the tightly

jammed state between the housing 101 and the slope surface 122. However, the clutch member 140 keeps in contact with the housing 101 and the slope surface 122, because the piston 130 forces the clutch member 140 outward by the biasing force of the spring 135.

Therefore, when the wrench 100 is rotated again in a clockwise direction, no free play of the wrench 100 occurs, and the rotating force is

immediately transmitted to the fastening body 120 and subsequently to the fastener 300.

Because free play does not occur during repetition of the power stroke and the free stroke, the fastener 300 can be more easily tightened or loosened even when the space for operating the wrench 100 is very small due to nearby obstacles.

Furthermore, because the clutch member 140 keeps in contact with the housing 101 and the slope surface 122 of the fastening body 120 due to the biasing force of the spring 135, free play is minimized even when a constituent part, for example the clutch member 140, of the wrench 100 wears.

While this invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed

embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A wrench, comprising: a housing having an interior hole; a handle for supplying torque to the housing; and a fastening unit, being disposed in the interior hole of the housing, rotatable in one direction relative to the housing.

2. The wrench of claim 1 , wherein the fastening unit comprises: a fastening body having an exterior circumference, wherein a slope surface is formed at the exterior circumference such that a depth of the slope surface from the exterior circumference increases as a distance from an outward end of the slope surface increases; a clutch member disposed between the slope surface and the housing; and an elastic unit adapted to provide an outward biasing force to the clutch member.

3. The wrench of claim 2, wherein the slope surface is planar.

4. The wrench of claim 2, wherein a cross-section of the clutch member is circular such that the clutch member can roll on the slope surface.

5. The wrench of claim 2, wherein the elastic unit comprises: an elastic member abutted by the fastening body; and

a piston disposed between the elastic member and the clutch member.

6. The wrench of claim 5, wherein: an operation hole, having a predetermined angle with the slope i surface, is formed at an end of the slope surface; and the elastic member and the piston are disposed in the operation hole.

7. The wrench of claim 2, wherein a plurality of slope surfaces are symmetrically provided.